Energy absorbing bumper structures for automotive vehicles have been found to be an effective means for reducing damage resulting from low speed collisions. One type of energy absorbing bumper which gives favorable results comprises a hollow elastomeric shell mounted to a rigid backing member. The hollow shell has integrally formed partitions or baffles to increase its stiffness and energy absorbing capacity. Difficulties have been encountered in the selection or development of materials having adequate energy absorption over a necessarily wide range of temperatures and also providing a smooth paintable finish.
Another type of elastomeric bumper known in the art is that having a plastic "egg crate" or honeycomb within an elastomeric cover and mounted to a backing member.
This invention provides an elastomeric bumper construction in which the local stress concentrations induced in the energy absorbing members from an impact are significantly reduced. It also provides a construction in which the energy absorbing members are so designed as to deform along predetermined locations. In addition, the invention provides substantially full recovery of the energy absorbing members following impact. Further, this invention provides an elastomeric bumper assembly having composite materials in which one material suitable for finishing is used on the outer cover and a second material suitable for energy absorption under a variety of temperature conditions is used for the energy absorbing components. Further, this invention provides an elastomeric bumper assembly in which the shape or contours of the exterior surfaces are unaffected by the position and presence of the energy absorbing components.
A resilient bumper assembly constructed in accordance with this invention includes (1) a rigid elongate backing member extending transversely of the automotive vehicle, (2) an elastomeric outer shell secured to the backing member, and (3) separate energy absorbing means received within the outer shell and abutting the backing member. The energy absorbing means include a plurality of elastomeric bellows elements having their axes positioned essentially parallel to the direction of travel of the vehicle.